Use of chalcopyrite semiconductors CuXSe2 (X=Al,Ga and In) in solar cells: a theoretical study

The energy of sunlight falling on surface of the earth can be directly converted into electricity by means of the solar cells. Among the various materials used for photovoltaics, the chalcopyrite compounds CuXSe₂ (X=Al, Ga, In) are very promising as semiconductors and have received much attention in the recent years. To check the applicability of these materials in solar cells, we have computed the energy bands, density of states, optical dielectric tensors, reflectivity, refraction and absorption coefficients using the full potential linearized augmented plane wave method. It is seen that the energy bandgap reduces from X=Al→In. The dielectric property of these materials is discussed in terms of interband transitions. The absorption coefficients of these materials in the region of solar radiation (0–5 eV energy) are discussed to explore their use in the fabrication of solar cells.